WORKER REPRODUCTION AND SOCIAL HIERARCHIES IN LEPTOTHORAX ANTS

Kin selection theory predicts the existence of potential conflict betw een queen and workers and among workers concerning the production of m ales in insect societies with a single, once-mated queen. We investiga ted the occurrence of reproductive conflict and worker reproduction in both single- and multi-queen colonies of 10 species of the ant genus Leptothorax. In contrast to previous observations in related species, workers only infrequently engaged in aggressive interactions and did n ot lay large numbers of eggs in colonies containing queens. Allozyme a nalyses of queens, workers and males suggest that the contribution of workers to the males produced in colonies with queens is indeed minima l, at least in L. unifasciatus. When the queens died or were experimen tally removed from the colonies, in most species dominance interaction s among workers became significantly more frequent and one or several high-ranking workers started to lay eggs. Workers with an increased nu mber of ovarioles per ovary apparently had a reproductive advantage ov er workers with normal ovaries. (C) 1997 The Association for the Study of Animal Behaviour.